Nested allostery in scorpion hemocyanin (Pandinus imperator).
The oxygen-binding behavior of the 24-meric hemocyanin of the scorpion Pandinus imperator and its dependence on allosteric effectors such as protons can be successfully described by the nesting model; the MWC model is not acceptable. The affinities of the four assumed conformations of the allosteric unit, the 12-meric half-molecule, are not dependent on pH whereas the three allosteric equilibrium constants decrease with decreasing proton concentration. Comparison with the oxygen-binding behavior of the 24-meric tarantula hemocyanin (Eurypelma californicum) reveals that the affinity values for the various conformations seem to be conserved for chelicerata hemocyanin.
Decker
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Zoologisches Institut der Universität München, F.R.G.
D000495:Allosteric Site; D000818:Animals; D001665:Binding Sites; D006433:Hemocyanins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046911:Macromolecular Substances; D008962:Models, Theoretical; D010100:Oxygen / Q000378:metabolism; D011487:Protein Conformation; D012605:Scorpions
D046911:Macromolecular Substances; D006433:Hemocyanins; D010100:Oxygen